It is known to use an incinerator to burn combustible waste material that has been contaminated by radioactive substances. Through incineration the volume of the waste material is reduced to ash and recovery of radioactive particles is made possible. Any substantial accumulation in the incinerator of radioactive ash creates the danger that the ash will reach its critical mass. To obviate this problem, special apparatus is used in prior art incinerators for removing such ash. Generally, hydraulically operated plows which scrape the floor are utilized to push ash toward an ash trough for further collection. The use of such equipment raises the possibility that an excessive amount of radioactive ash may be retained beneath the plow as it retracts following its forward travel. If the radioactivity exceeds a predetermined level, the incinerator must be shut down for cleaning. Such a shut-down results in the loss of useful operating time and thus lowers the overall efficiency of the operation.
In many prior art incinerators, the burning waste material is successively moved down a series of stepped levels inside the incinerating chamber. On the top level of the chamber, floor debris consisting of burning waste and whatever ash has accumulated, are cleared by the subsequently loaded waste material. In effect, the newly loaded waste pushes the old floor debris ahead of itself and down to the next floor level. Therefore, once the last load of waste has been placed into the incinerator and has been reduced to ash, partially or completely, the ash remains on the upper level and no means are provided for its removal.